I am struggling to decide how to configure the 21" iMac I am ready to buy. I had decided on Fusion Drive and leaving the RAM at 8GB, even knowing I can't upgrade later. I now wonder whether I would be better getting a 256GB SSD instead and getting an external drive to hook up via USB. Would I notice the difference? I'm likely to be using Aperture (iPhoto initially) but not taxing it too much - general management of prosumer DSLR photos and minor image processing but not heavy image manipulation. I may use Windows occasionally through bootcamp but can't see me getting Parallels. I'm struggling to justify buying a desktop as it is, so upgrading storage and RAM is pushing it, but my 2010 MBA is full and unsuitable for lots of photo work. On that basis, maybe I'm talking myself into upgrading the base model storage and not going for the discrete graphics of the better 21" model! I had assumed though that the 1GB GT 750M was a worthy upgrade for £150. Advice appreciated.